We searched for violations of the weak equivalence principle using a cryogenic torsion balance with a pendulum comprised of superconducting niobium and copper. We constrain the E\"otv\"os parameter with 95%-confidence to ηNb*-Cu≤2.0×10−9 and ηCP-ee≤9.2×10−4 for superconducting niobium and Cooper pairs, respectively.
@article{arxiv.2407.21232,
title = {Test of the Equivalence Principle for Superconductors},
author = {M. P. Ross and S. M. Fleischer and I. A. Paulson and P. Lamb and B. M. Iritani and E. G. Adelberger and C. A. Hagedorn and K. Venkateswara and C. Gettings and E. A. Shaw and S. K. Apple and J. H. Gundlach},
journal= {arXiv preprint arXiv:2407.21232},
year = {2024}
}